High PPI (Pixels Per Inch) is always an important target in the display field, and has once become an important selling point of products such as mobile phones and televisions. However, high PPI also brings some disadvantages while bringing advantages such as good viewing effect. High PPI would result in increase of the data processed by the GPU (Graphics Processing Unit), thereby resulting in large power consumption of the battery.
Actually, the resolution of human eyes is not always invariable; it generally varies at any moment based on distance, environments, and running speeds of images. An important theory is the “retina” standard proposed by Apple Inc. that when the viewer is 10-12 inches (about 25-30 cm) from the display screen, and as long as the resolution of the display screen reaches 300 ppi (300 pixel points per inch) and above, the viewer's retina will not be able to identify the pixel points, i.e., granular sensation will not be perceived.
Therefore, when human eyes are very close to a mobile phone, in order to prevent consumers from seeing minor flaws on the display screen, and try to show the perfect picture, the high resolution of the mobile phone itself can be used. However, when the screen is relatively far from the user, even if the resolution does not meet the above one, the user would not be able to identify the pixel points either; therefore, it is unnecessary to always keep the display screen at a relatively high resolution so as to result in excessive consumption of electricity.